Fernando Torres missed Atletico Madrid training on Tuesday due to a knee injury.
Torres scored Atletico's second goal in Sunday's 3-1 win at Valencia less than 10 minutes after coming on as a substitute, as Diego Simeone's side kept their faint La Liga title hopes alive.
But Atletico revealed on Tuesday that the former Liverpool and Chelsea striker picked up a knock to his right knee at Mestalla, which will be monitored after rendering him unable to train.
"Fernando Torres was not able to train with the rest of his team-mates in the first session of the week," read a club statement.
"After the fixture against Valencia, Atletico's striker felt discomfort in his right knee. He underwent diagnostic imaging tests (MRI) in Majadahonda's Fremap Clinic, and the medical report of Fernando Torres indicates that he is suffering a traumatic injury to the right knee that has caused swelling and pain.
"He will undergo medical and physical therapy treatment. He is pending evolution."
Victory at Mestalla kept Atletico within eight points of Barcelona at the top of La Liga.
They host Deportivo La Coruna on Saturday, before entertaining PSV in the second leg of their Champions League last-16 tie next Tuesday.